package com.filter;

import com.enumeration.ResponseEnum;
import com.shiro.JwtToken;
import com.utils.JwtUtil;
import lombok.extern.log4j.Log4j2;
import org.apache.commons.lang3.StringUtils;
import org.apache.shiro.authz.UnauthorizedException;
import org.apache.shiro.web.filter.authc.BasicHttpAuthenticationFilter;
import org.springframework.web.bind.annotation.RequestMethod;

import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.net.URLEncoder;
import java.util.Date;


/**
 * Response.java
 *
 * @author Liang 649355204@qq.com
 * CreateTime 2019/7/16 09:09
 */
@Log4j2
public class JwtFilter extends BasicHttpAuthenticationFilter {
    private static final String TOKEN_EXPIRED = "token_expired";

    /**
     * 如果带有 token，则对 token 进行检查，否则直接通过
     */
    @Override
    protected boolean isAccessAllowed(ServletRequest request, ServletResponse response, Object mappedValue) throws UnauthorizedException {
        //判断请求的请求头是否带上 "Token"
        if (isLoginAttempt(request, response)) {
            //如果存在，则进入 executeLogin 方法执行登入，检查 token 是否正确
            try {
                executeLogin(request, response);
                return true;
            } catch (Exception e) {
                //token 错误
                if(TOKEN_EXPIRED.equals(e.getMessage())){
                    System.out.println("--------");
                    tryRefreshToken(request, response, 401);
                }else{
                    responseError(response, ResponseEnum.UNAUTHENTICATED_ERROR.getMsg());
                }
            }
        }
        //如果请求头不存在 Token，则可能是执行登陆操作或者是游客状态访问，无需检查 token，直接返回 true
        return true;
    }
    /**
     * 返回状态码
     * @apiDefine TokenExpiredException
     * @apiError 332 <code>TokenExpiredException</code> 缺少参数或必要参数为空
     * @apiErrorExample {json} 332
     * HTTP/1.1 332 TokenExpiredException
     *     {
     *     "resultCode": 452,
     *     "resultMsg": "缺少参数或必要参数为空",
     *     "data": {},
     *     "errCode": 0,
     *     "errMsg": null
     *     }
     * */
    private void tryRefreshToken(ServletRequest request, ServletResponse response, int code) {
        HttpServletRequest req = (HttpServletRequest) request;
        HttpServletResponse httpServletResponse = (HttpServletResponse) response;
        String token = req.getHeader("Authorization");
        if(!StringUtils.isEmpty(token)){
            String uuid = JwtUtil.getUuid(token);
            System.out.println("refresh");
            log.debug("==========================refresh======================");
            log.debug(String.valueOf(uuid));
            httpServletResponse.setStatus(332);
            log.debug("==========================refresh======================");
            Date refreshTime = JwtUtil.getRefreshTime(token);
            System.out.println(refreshTime);
            System.out.println(refreshTime.after(new Date()));
            if(!StringUtils.isEmpty(token) && refreshTime!=null &&refreshTime.after(new Date())){
                httpServletResponse.addHeader("Authorization", JwtUtil.createToken(uuid));
                System.out.println("重置header");
                log.debug("==========================重置header======================");
                httpServletResponse.setStatus(401);
                log.debug("==========================重置header======================");
            }else{
                httpServletResponse.setStatus(332);
            }
        }else{
            httpServletResponse.setStatus(332);
        }
    }

    /**
     * 判断用户是否想要登入。
     * 检测 header 里面是否包含 Token 字段
     */
    @Override
    protected boolean isLoginAttempt(ServletRequest request, ServletResponse response) {
        HttpServletRequest req = (HttpServletRequest) request;
        String token = req.getHeader("Authorization");
        return token != null;
    }

    /**
     * 执行登陆操作
     */
    @Override
    protected boolean executeLogin(ServletRequest request, ServletResponse response) throws Exception {
            HttpServletRequest httpServletRequest = (HttpServletRequest) request;
        String token = httpServletRequest.getHeader("Authorization");
        JwtToken jwtToken = new JwtToken(token);
        // 提交给realm进行登入，如果错误他会抛出异常并被捕获
         getSubject(request, response).login(jwtToken);
        // 如果没有抛出异常则代表登入成功，返回true
        return true;
    }

    /**
     * 对跨域提供支持
     */
    @Override
    protected boolean preHandle(ServletRequest request, ServletResponse response) throws Exception {
        HttpServletRequest httpServletRequest = (HttpServletRequest) request;
        HttpServletResponse httpServletResponse = (HttpServletResponse) response;
        httpServletResponse.setHeader("Access-control-Allow-Origin", httpServletRequest.getHeader("Origin"));
        httpServletResponse.setHeader("Access-Control-Allow-Methods", "GET,POST,OPTIONS,PUT,DELETE");
        httpServletResponse.setHeader("Access-Control-Allow-Headers", httpServletRequest.getHeader("Access-Control-Request-Headers"));
        httpServletResponse.setHeader("Access-Control-Expose-Headers", "Authorization, Content-Disposition");

        // 跨域时会首先发送一个option请求，这里我们给option请求直接返回正常状态
        if (httpServletRequest.getMethod().equals(RequestMethod.OPTIONS.name())) {
//            httpServletResponse.setStatus(HttpStatus.OK.value());
            return false;
        }
        return super.preHandle(request, response);
    }

    /**
     * 将非法请求跳转到 /unauthorized/**
     */
    private void responseError(ServletResponse response, String message) {
        try {
            HttpServletResponse httpServletResponse = (HttpServletResponse) response;
            //设置编码，否则中文字符在重定向时会变为空字符串
            message = URLEncoder.encode(message, "UTF-8");
            httpServletResponse.sendRedirect("/unauthorized/" + message);
        } catch (IOException e) {
            log.error(e.getMessage());
        }
    }
}
